Adjustable preset pressure-actuated mechanical prime mover

ABSTRACT

The disclosure involves a snap acting mechanical prime mover which is actuated by a preset fluid pressure and can be adjusted to be actuated by any desired preset pressure within the range of the prime mover. The prime mover will move outwardly and return when the actuating pressure reaches a preset level. Upon release of the actuating pressure the prime mover resets for another cycle.

United States Patent Forrest L. Carson Box 1594, Borger, Tex. 79007 Sept. 8, 1969 Oct. 19, 1971 Continuation-impart of application Ser. No. 683,293, 1991. 15, 1967, now I ate tNo.

lnventor Appl. No, Filed Patented ADJUSTABLE PRESET PRESSURE-ACTUATED MECHANICAL PRIME MOVER 3 Clnlms, 3 Drawing Figs.

U.S. Cl 137/612.1, 137/469, 91/395, 91/410, 92/80, 92/169 Int. Cl ..F15b 15/22,

[50] Field oisearch 137/469;

[56] References Cited UNITED STATES PATENTS 2,361,084 10/1944 Canetta 137/204 2,556,867 6/1951 Carlisle 137/155 X 3,465,647 9/1969 Carson 91/395 Primary Examiner-Alan Cohan ABSTRACT: The disclosure involves a snap acting mechanical prime mover which is actuated by a preset fluid pressure and can be adjusted to be actuated by any desired preset pressure within the range of the prime mover. The prime mover will move outwardly and return when the actuating pressure reaches a preset level. Upon release of the actuating pressure the prime mover resets for another cycle.

ADJUSTABLE PRESE'I PRESSURE-ACTUATED MECHANICAL PRIME MOVER This application is a continuation-in-part of my copending application Ser. No. 683,293 filed Nov. 15, l967, entitled, Adjustable Preset Pressure Actuated Mechanical Prime Mover now U.S. Pat. No. 3,465,647.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is directed to a snap-acting fluid pressure mechanical prime mover for operating numerous devices such as valves, electric switches, triggers, pilot members, safety devices and the like.

2. Description of the Prior Art Prior to the present invention pressure actuated mechanical prime movers were such that movement of the device was directly related to the working pressure. Such devices were not capable of providing an instant recycling snap-acting device such as the present invention. Other devices utilize an over dead center mechanical means to obtain a snap action, but these too fail to provide the instant recycling snap action of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross section of the invention showing a port for diverting the fluid pressure to another piloted device.

FIG. 2 is a vertical cross section of the invention showing the lower valve omitted.

FIG. '3 is a vertical cross section showing the invention arranged for fluid pressure biasing means.

Referring now to the drawings in detail wherein like reference characters indicate like parts throughout the several figures, the reference numeral indicates generally a preset pressure actuated mechanical prime mover constructed in accordance with the invention.

The prime mover 10 includes a body 11 having a longitudinally extending threaded bore 12 opening inwardly from the outer end thereof A cylindrical valve chamber 13 is formed centrally of the body 11 in communication with the bore 12 and having a diameter somewhat greater than that of the bore 12. A second threaded bore 14 opens inwardly from the inner end of the body 11 and communicates with the chamber 13. The second bore 14 has a diameter substantially greater than the diameter of the chamber 13 as can be clearly seen in FIGS. 6 through 8. The bore 12, chamber 13, and bore 14 are formed on a common axis.

An externally threaded cylinder 15 is threaded into the threaded bore 14 at one end and extends outwardly therefrom. The threaded cylinder 15 is provided with a pair of oppositely disposed elongated longitudinally extended slots 16.

A resilient double valve seat member 17 is molded onto a washer 18 and is positioned so as to extend into the chamber 13 in sealing engagement therewith. The washer 18 engages the shoulder 19 between the threaded bore 14 and the chamber 13 and is clamped thereto by the inner end of the cylinder 15.

A generally flat valve 20 is positioned within the chamber 13 for reciprocal movement therein into and out of engagement with a valve seat 21 on the double valve seat member 17 The valve 20 has a dimple formed centrally thereof at 22 for reasons to be assigned..A tapered coil spring 23 is positioned in the chamber 13 in engagement with the shoulder 24 at one end of the chamber 13. The opposite end of coil spring 23 engages the valve 20 with the upper end of spring 23. The lower end of the coil spring 23 has a diameter to snugly fit the wall of the chamber 13.

A cylindrical piston 25 is positioned within the cylinder 15 I and is adapted to reciprocate therein. The piston 25 has an outwardly extending conical valve 26 formed centrally of the lower end thereof adapted for engagement with a depressed conical valve seat 27 formed on the double valve seat member 17. A central bore 28 is formed in the piston 25 opening through the valve 26 at the lower end thereof and terminating short of the-opposite end of the piston 25. A free valve stem 29 is mounted in the bore 28 for reciprocation therein andhas at its upper end a reduced diameter guide pin 30 as can be seen in FIGS. 6 and 8. A coil spring 31 is mounted in the bore 28 in engagement with the upper end thereof with its lower end engaging over the guide pin 30 to resiliently bias the valve stem 29 into engagement with the valve 20. The lower end of the valve stem 29 is centered in the recessed portion of the dimple '22 in the valve 20. The upper end of the piston 25 has a reduced diameter spring guide portion 32 to receive the lower end of a coil spring 33 positioned in the cylinder 15. A movable spring seat 34 is in engagement with the upper end of the spring 33 and has a pair of oppositely extending ears 35 which project through the slots 16 outwardly of the cylinder 15. An adjusting nut 36 is threaded onto the externally threaded cylinder 15 and is adapted to engage the ears to move the movable spring seat 34 longitudinally of the cylinder 15 to the extent permitted by the length of the slots 16. An actuator pin 37 is integrally formed on the piston 25 and extends axially therefrom oppositely of the valve 26.

A pilot pressure port 57 is provided on cylinder 15, and extends therethrough at a point immediately above double valve seat 17.

Referring now to FIG. 1 the operation of the prime mover 10 will now be explained. The threaded bore 12 is connected to a source of fluid pressure, either hydraulic or pneumatic, and with the pressure at zero the parts of the prime mover will be in the position as shown in FIG. 1. As the pressure develops in the system the fluid flows into the valve chamber 13, around the valve 20, through a central port 56 in the double valve seat 17 and is prevented from flowing further by contact of the valve 26 with the valve seat 27. As the pressure increases to the preset point the piston 25 remains in its lower most position with the valve 26 sealed to the seat 27. As the pressure reaches the preset point the fluid will lift the piston slightly off of the valve seat 27 against the pressure of the spring 33, exposing the whole lower end of the piston 25 to the pressure. As soon as the whole lower end of the piston 25 is exposed to the pressure the piston 25 snaps upwardly in the cylinder 15 ad mitting pressure to the cylinder 15 this pressure is communicated to pilot pressure port 57, to pilot pressure pipe 58, and on to any pilot pressure operated device as desired. During this brief period the speed at which the piston travels upwardly is somewhat retarded. As soon as the pilot pressure operated device is actuated, and the pressure in the pilot system builds the piston 25 is accelerated in its upward travel until the valve 20 comes in contact with seat 21 sealing the fluid pressure against further passage of the fluid into the cylinder 15 and the fluid already therein now bleeds past the piston 25, and the piston 25 is snapped downwardly by the spring 33 into sealing engagement with the valve seat 27. Pressure in the pilot pressure pipe 58 returns through pilot pressure port 57 into the cylinder 15, and bleeds past the piston 25. Even though pressure is maintained on the system the valve 20 will remain in sealed position against the valve seat 21 and all of the remaining parts of the prime mover 10 will remain in this position until the pressure is released from the system, whereupon the valve 20 will move to the position illustrated in FIG. 1, resetting the parts for another cycle. The adjusting nut 36 can be moved on the cylinder 15 to increase or decrease the spring pressure brought to bear on the piston 25 so as to adjust the point in pressure at which the piston 25 will be cracked from the valve seat 27. The floating valve stem 29 and the spring 31 are capable of keeping the valve 20 spaced from the seat 21 against the pressure of the spring 23 as illustrated in FIG. I. However the spring 31 is insufficient to move the valve 20 away from the seat 21 so long as pressure in the system is bearing there against.

Referring now to FIG. 2 the operation of the prime mover 10 as illustrated in FIG. 7 will be explained. The threaded bore 12 is connected to a source of fluid pressure, either hydraulic or pneumatic, and with the pressure at zero the parts of the prime mover will be in the position as shown in FIG. 2 As pressure develops in the system the fluid flows into the valve chamber 13, through a central port 56 in the double valve seat 17 and is prevented from flowing further by contact of the valve 26 with the valve seat 27. As the pressure increases to the preset point the fluid will lift the piston slightly off of the valve seat 27 against thepressure of the spring 33, exposing the whole lower end of the piston 25 to the pressure. As soon as the whole lower end of the piston 25 is exposed to the pres sure the piston 25 snaps upwardly in the cylinder 15 until travel is limited by total collapse of spring 33. The piston 25 will hold this position so long as pressure is maintained on the system. When the pressure is released the piston 25 is snapped downwardly by the spring 33 into sealing engagement with the valve seat 27. The parts are now in the position as shown in FIG. 2, and the prime mover is ready for another cycle. The adjusting nut 36 can be moved on the cylinder to increase or decrease the spring pressure brought to bear on the piston 25 so as to adjust the point in pressure at which the piston 25 will be cracked from the valve seat 27.

Referring now to FIG. 3 the cylinder 15 is provided with a small bore 60 with the actuator pin 37 a sliding fit therein, a cylinder vent 59, a fluid pressure port 61, with a fluid pressure pipe 62, and a pressure regulator 63 attached thereto. Piston 25 has a grooved section 64 which is aligned at each end of the stroke with cylinder vent 59, and in communication therewith at all times. The operation of the prime mover 10 as illustrated in FIG. 8 will now be explained. Fluid pressure is applied .to pressure regulator 63, or directly to fluid pressure pipe 62 this pressure is communicated to fluid pressure port 61 through fluid pressure pipe 62, and comes to bear against the upper portion of the piston 25, biasing the piston 25 into sealing engagement with the double valve seat 27. The amount of fluid pressure bearing against the upper portion of the piston 25 establishes the point in pressure at which the prime mover 10 will actuate, when fluid pressure is applied to the threaded bore 12. The threaded bore 12 is now connected to a source of fluid pressure, either hydraulic or pneumatic, and with the pressure at zero the parts of the prime mover will be in the position as shown in FIG. 3. As the pressure develops in the system the fluid flows into the valve chamber 13, around the valve 20, through central port 56 in the double valve seat 17 and is prevented from flowing further by contact of the valve 26 with the valve seat 27. As the pressure increases to the preset point the piston 25 remains in its lower most position with the valve 26 sealed to the seat 27. As the pressure reaches the preset point the fluid will lift the piston 25 slightly off of the valve seat 27 against the pressure of the fluid pressure bearing against the upper portion of the piston 25, exposing the whole lower end of the piston 25 to the pressure. As soon as the whole lower end of the piston 25 is exposed to the pressure, the piston 25 snaps upwardly in the cylinder 15 until the valve comes in contact with the valve seat 21, sealing the fluid pressure against further passage of the fluid into the cylinder 15, and the fluid already therein now bleeds past the piston into the grooved section 64 of the piston 25, and is vented to the atmosphere through cylinder vent 59, and the piston 25 is snapped downwardly by thefluid pressure bearing against the upper portion of the piston 25 into sealing engagement with the valve seat 27. Even though pressure is maintained at threaded bore 12, the valve 20 will remain in sealed position against the valve seat 21, and all of the remaining parts of the prime mover 10 will remain in this position until the pressure is released from bore 12, whereupon the valve 20 will move to the position illustrated in FIG. 3, resetting the parts for another cycle. The fluid pressure brought to bear upon the upper portion of the piston 25 can be adjusted up or down through pressure regulator 63, so as to adjust the point at which rising pressure in the threaded bore 12 will cause the piston 25 to be cracked from valve seat 27. If sustained pressure is applied to fluid pressure port 61, and regulated pressure is applied to the threaded bore 12, the prime mover 10 can be made to actuate at any point of decline of the sustained pressure at fluid pressure port 61.

claim:

1. A snap-acting adjustable pressure-actuated prime mover comprising a cylinder, said cylinder having a side port for diverting fluid pressure, a piston mounted for reciprocation in said cylinder, a valve seat at one end of said cylinder, said valve seat having a central port extending therethrough and communicating with a source of fluid pressure, a valve on said piston engageable with said valve seat and sealing said central port against the passage of fluid, resilient means biasing said piston and said valve into sealing engagement with said valve seat to maintain said valve in engagement with said valve seat until the fluid pressure exceeds a preset point, said valve having an area exposed to the pressure substantially less than the cross-sectional area of said piston, and valve means for closing the pressure side of said central port upon movement of said piston in said cylinder away from said valve seat, and resilient means on said piston for opening said valve means upon movement of said piston in said cylinder toward said valve seat.

2. A snap-acting adjustable pressure-actuated prime mover comprising a cylinder, a piston mounted for reciprocation in said cylinder, a valve seat at one end of said cylinder, said valve seat having a central port extending therethrough and communicating with a source of fluid pressure, a valve on said piston engageable with said valve seat and sealing said central port against the passage of fluid, fluid pressure resilient means biasing said piston and said valve into sealing engagement with said valve seat to maintain said valve in engagement with said valve seat until the fluid pressure exceeds a preset point, said valve having an area exposed to the pressure substantially less than the cross-sectional area of said piston, and valve means for closing the pressure side of said central port upon movement of said piston in said cylinder away from said valve seat, and resilient means on said piston for opening said valve means upon movement of said piston in said cylinder toward said valve seat.

3. A snap-acting adjustable pressure-actuated prime mover as claimed in claim 2, with means for adjusting the pressure of said fluid pressure resilient biasing means. 

1. A snap-acting adjustable pressure-actuated prime mover comprising a cylinder, said cylinder having a side port for diverting fluid pressure, a piston mounted for reciprocation in said cylinder, a valve seat at one end of said cylinder, said valve seat having a central port extending therethrough and communicating with a source of fluid pressure, a valve on said piston engageable with said valve seat and sealing said central port against the passage of fluid, resilient means biasing said piston and said valve into sealing engagement with said valve seat to maintain said valve in engagement with said valve seat until the fluid pressure exceeds a preset point, said valve having an area exposed to the pressure substantially less than the cross-sectional area of said piston, and valve means for closing the pressure side of said central port upon movement of said piston in said cylinder away from said valve seat, and resilient means on said piston for opening said valve means upon movement of said piston in said cylinder toward said valve seat.
 2. A snap-acting adjustable pressure-actuated prime mover comprising a cylinder, a piston mounted for reciprocation in said cylinder, a valve seat at one end of said cylinder, said valve seat having a central port extending therethrough and communicating with a source of fluid pressure, a valve on said piston engageable with said valve seat and sealing said central port against the passage of fluid, fluid pressure resilient means biasing said piston and said valve into sealing engagement with said valve seat to maintain said valve in engagement with said valve seat until the fluid pressure exceeds a preset point, said valve having an area exposed to the pressure substantially less than the cross-sectional area of said piston, and valve means for closing the pressure side of said central port upon movement of said piston in said cylinder away from said valve seat, and resilient means on said piston for opening said valve means upon movement of said piston in said cylinder toward said valve seat.
 3. A snap-acting adjustable pressure-actuated prime mover as claimed in claim 2, with means for adjusting the pressure of said fluid pressure resilient biasing means. 